Size distribution effect on the magnetization and magnetoresistance in ferromagnetic nanostructured manganites

D. GARCÍA; B. ALASCIO; D.G. LAMAS; D. NIEBIESKIKWIAT; A. CANEIRO; R.D. SÁNCHEZ; E.D. CABANILLAS

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS

Elsevier

Año: 2005 vol. 66 p. 1687 - 1694

0022-3697

We present experimental data of magnetization and magneto-resistance of nanostructured La2/3B1/3MnO3 with B=Ca;Sr, which present difference between the coercive field in the magnetization loop with their corresponding maximum value in the magneto-resistance. Thisdifference is described by a model that include, size distribution of magnetic particles, randomly oriented anisotropy axis and electronic transfer between the particles, which is mediated by spin-polarized tunneling process. Also, the model predicts that the maximum magnetoresistance can be, in the magnetic disorder state, two times larger than the experimental value. The model results can be used to estimate the size dispersion of nanoparticles in similar systems.